1. Field of the Invention
The present invention relates to a steel product with heat-resistant, corrosion-resistant plating layers, and more particularly, to a steel product such as sheets, pipes, couplings, clamps, bolts, and nuts used for automobiles and various machines and equipment, said steel product having heat-resistant, corrosion-resistant plating layers on the surface thereof.
2. Description of the Prior Art
It has been a common practice to form a zinc plating layer and then a chromate film on sheets, pipes, couplings, clamps, bolts, and nuts used for automobiles and various machines and equipment. Conventional plated steel products exhibit improved corrosion resistance in corrosive environments at normal temperature but they do not in high-temperature environments such as automotive engine rooms.